1. Field of the Invention
The present invention relates to a viscous liquid heater using viscous liquid and a rotor to convert rotation energy into thermal energy.
2. Description of the Related Art
A viscous liquid heater for a vehicle is disclosed in U.S. Pat. No. 4,993,377 or JP-A-2-246823. However, it is necessary to provide an electromagnetic clutch to control a rotor of the viscous heater to generate heat. This requires considerable space of the vehicle to install such a heater, and heat generation control according to various conditions is very difficult.
JP-A5-8633 discloses another viscous liquid heater which has a viscous liquid joint section and a compressor section installed in a unit. Although the liquid joint section is used as a heater section when the compressor is stopped, it is impossible to operate both the heater section and the compressor section for a dehumidification. It is also difficult to control temperature of the heater section according to various conditions.